//查询语句
//SELECT id,username,phone,sex from dsc_user
//查询dsc_user表中年龄等于18
// SELECT * FROM dsc_user WHERE age=18
//查询dsc_user表中年龄等于18或者年龄等于28
// SELECT * FROM dsc_user WHERE age = 18 OR age = 28
//查询dsc_user表中年龄等于18并且手机号为13673618137的数据
// SELECT * from dsc_user WHERE age = 18 AND phone = "13673618137"

//根据年龄排序
// SELECT * from dsc_user ORDER BY age DESC      //DESC降序   ASC升序

// 插入
// INSERT INTO dsc_user SET username ="lisi", password ="123456", phone ="110", is_show = 1, create_time = "2021-01-18 16:50:00"